From: Paolo Bonzini <pbonzini@redhat.com>
To: Eduardo Habkost <ehabkost@redhat.com>, Thomas Huth <thuth@redhat.com>
Cc: qemu-arm <qemu-arm@nongnu.org>,
QEMU Developers <qemu-devel@nongnu.org>,
Markus Armbruster <armbru@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>
Subject: Re: [Qemu-devel] [PATCH] hw/arm/bcm283x: Fix crash with device_add bcm2837 on unsupported machines
Date: Thu, 12 Jul 2018 10:04:48 +0200 [thread overview]
Message-ID: <8275fafc-7f3b-616e-5702-7595ed1466be@redhat.com> (raw)
In-Reply-To: <20180711195924.GC7451@localhost.localdomain>
On 11/07/2018 21:59, Eduardo Habkost wrote:
>
> What exactly guarantees there will be no other references to
> (e.g.) `&s->control` when `s` is freed?
>
> We know the references added by object_initialize(),
> object_property_add_child() and qdev_set_parent_bus() will be
> dropped, but what about other code calling object_ref()?
That would be a bug. This is in fact the reason why
memory_region_ref/unref exists---to take the reference on the "outer"
device object rather than the contained memory region object. It's not
pretty though.
I've thought of generalizing the pattern to Object (object_ref adds a
reference to the container rather than the contained object, and
finalize takes care of finalizing the contained object too), but I'm a
bit wary of doing it since it would complicate things further and
(except for MemoryRegions) it hasn't been a problem in practice.
Paolo
next prev parent reply other threads:[~2018-07-12 8:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 21:03 [Qemu-devel] [PATCH] hw/arm/bcm283x: Fix crash with device_add bcm2837 on unsupported machines Thomas Huth
2018-07-09 21:31 ` Eduardo Habkost
2018-07-09 21:36 ` Thomas Huth
2018-07-09 21:42 ` Peter Maydell
2018-07-09 22:03 ` Thomas Huth
2018-07-10 6:50 ` Peter Maydell
2018-07-11 7:21 ` Thomas Huth
2018-07-11 16:12 ` Eduardo Habkost
2018-07-11 17:15 ` Peter Maydell
2018-07-12 12:06 ` Markus Armbruster
2018-07-12 12:55 ` Peter Maydell
2018-07-12 13:19 ` Markus Armbruster
2018-07-12 15:25 ` Thomas Huth
2018-07-12 16:16 ` Markus Armbruster
2018-07-12 16:22 ` Peter Maydell
2018-07-12 16:32 ` Thomas Huth
2018-07-16 6:41 ` Markus Armbruster
2018-07-11 17:21 ` Paolo Bonzini
2018-07-11 19:04 ` Thomas Huth
2018-07-11 19:59 ` Eduardo Habkost
2018-07-12 8:04 ` Paolo Bonzini [this message]
2018-07-12 12:04 ` Markus Armbruster
2018-07-11 17:20 ` Paolo Bonzini
2018-07-11 18:30 ` Eduardo Habkost
2018-07-11 20:16 ` Paolo Bonzini
2018-07-11 20:23 ` Eduardo Habkost
2018-07-12 8:05 ` Paolo Bonzini
2018-07-12 18:04 ` Eduardo Habkost
2018-07-16 6:43 ` Markus Armbruster
2018-07-16 14:25 ` Eduardo Habkost
2018-07-11 18:43 ` Thomas Huth
2018-07-11 20:15 ` Paolo Bonzini
2018-07-12 5:57 ` Thomas Huth
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